The present invention relates to a slide bearing material with aluminum as the basic material, consisting of an aluminum alloy with 10 to 25 weight-% of tin, and additions of copper, nickel and manganese.
Such a slide bearing material is known, for example, from German Patent, DE 40 04 703 A1. The single exemplary embodiment teaches an aluminum alloy of a composition of AlSn10Ni2Mn1Cu0.5, wherein a lead addition can also be used instead of the tin addition. With such aluminum alloys used as a slide bearing material, a xe2x80x9csoft phasexe2x80x9d in the form of a tin, or also lead precipitation is required for assuring good emergency running properties of a bearing made of the slide bearing material. Hard dirt particles and rubbed-off parts are taken up in this soft phase or are embedded in it. The soft phase can also be adapted to geometric conditions. The soft phase of tin, which cannot be dissolved in the aluminum, is contained in the form of block-shaped precipitations in the matrix-forming aluminum.
It is known to add copper to increase the strength of the aluminum matrix. Copper forms intermetallic phases with aluminum, so-called mechanically resistant material phases, such as Al2Cu and finely dispersed pre-stages thereof, which cause an increase in the strength of the aluminum if they are present in finely distributed precipitations (xe2x89xa61 xcexcm). The load carrying ability and fatigue resistance of a slide bearing material made from such an alloy is thus increased. Such an aluminum alloy. AlSn15Cu2 is known by the commercial name KS 985.3. This alloy which already has excellent tribologic properties, however, for applications under extreme load conditions, for example as a connecting rod bearing in modern internal combustion engines, requires improvement.
This was attempted to be achieved by the addition of manganese and nickel to the aluminum alloy known from previously noted German Patent, DE 40 04 703 A1, by means of which the proportion of the mechanically resistant material phase was intended to be increased namely, in accordance with the teaching contained in this Patent publication, in particular in the vicinity of the tin preparations, in order to achieve an improved bonding of the tin precipitation in the aluminum matrix because of the affinity of the tin for the nickel and the manganese.
There is also the belief that a certain proportion of mechanically resistant material phases or precipitations has a positive effect on good wear resistance in that on the surface the mechanically resistant material phases cause the finish grinding of the sliding partner, for example the crankshaft, so that the rough tips of the sliding partner made of steel can be worn off. The load bearing capacity of the bearing material is also said to be improved by the mechanically resistant material phases.
However, increases in the proportions of intermetallic mechanically resistant phases also entails problems with respect to fatigue resistance and also from the standpoint of production ability per se. For example, cracks occur during shaping, in particular when cold-cladding the aluminum alloy on steel, which requires a groove of approximately 50% shaping.
An object of the present invention is to improve an alloy of the type described at the outset in such a way that it has a greater load bearing capacity than the known aluminum-tin-copper or aluminum-tin-copper-nickel alloys, as well as an improved ability of being shaped, in particular being cladded.
This object is attained by a slide bearing material of the type mentioned at the outset, which is distinguished in that the copper, nickel and manganese each are present at a proportion of 0.2 to 2 weight-%, and that 0.2 to 2 weight-% of silicon is provided as a further addition, and that the ratio of the proportion in weight-% of copper to the proportion in weight-% of nickel, and the ratio of the proportion in weight-% of manganese to the proportion in weight-% of silicon lies between 0.6 and 1.2.